<template>
   <div>
     <router-link
      tag="div"
      to="/"
      class="header-abs"
      v-show="showAbs"
     >
       <div class="iconfont back-icon">&#xe646;</div>
     </router-link>
     <div
      class="header-fixed"
      v-show="!showAbs"
      :style="opactiyStyle"
     >
      <router-link to="/" >
        <div class="iconfont header-fixed-back">&#xe646;</div>
      </router-link>
      景点详情
     </div>
   </div>
</template>

<script>
export default ({
  name: 'DetailHeader',
  data () {
    return {
      showAbs: true,
      opactiyStyle: {
        opacity: 0
      }
    }
  },
  methods: {
    handleScroll () {
      const top = document.documentElement.scrollTop
      if (top > 60) {
        let opactiy = top / 140
        opactiy = opactiy > 1 ? 1 : opactiy
        this.opactiyStyle = { opactiy }
        this.showAbs = false
      } else {
        this.showAbs = true
      }
    }
  },
  activated () {
    window.addEventListener('scroll', this.handleScroll)
  },
  deactivated () {
    window.removeEventListener('scroll', this.handleScroll)
  }
})
</script>

<style lang="stylus" scoped>
  @import '~styles/varibles.styl'
  .header-fixed
    position: fixed
    top: 0
    left: 0
    right: 0
    height: $headerHeight
    line-height $headerHeight
    text-align center
    color #FFFFFF
    background-color: $bgColor
    font-size .32rem
    .header-fixed-back
      position absolute
      top 0
      left 0
      width .64rem
      text-align center
      font-size .4rem
      color #FFFFFF
  .header-abs
    position: absolute
    left: 0.2rem
    top: .2rem
    height: .8rem
    width: .8rem
    border-radius: .4rem
    line-height: .8rem
    align-content: center
    backgroud: rgba(0,0,0,.8)
    .back-icon
      color: #fff
      font-size: .4rem
</style>
